Process for the stabilization of petroleum lubricants



United States Patent .s,l92,163 PRGCESS FOR THE STABILIZATHON 0FTETROLEUM LUERTCANT Edward B. Hodge, Terre Haute, ind, assignor toCommercial Solvents Corporation, New York, N.Y., a corporation ofMaryland No Drawing. Filed Mar. 20, 1961, Ser. No. $6,676

=Claims. (Cl. 25249.5)

My invention relates to a stabilized petroleum lubricant and moreparticularly to a process for the production of stabilized petroleumlubricants containing as the active stabilizing agent nitroainineshaving the structural formula:

where R is lower alkyl and hydrogen and where R is selected from thegroup consisting of the radical N(R the morpholino radical and thepiperidyl radical and R is selected from the group consisting of loweralkyl, lower hydroxyl alkyl, and hydrogen.

It is well known that organisms from the groups consisting ofCorynebacterium, Achromobacter, lseudomonas, Nocardia and Mycobacteriummetabolize petroleum hydrocarbons and fatty acids and thereby produceundesirable oxidation products.

The petroleum industry has long been interested in the stabilization ofvarious petroleum products such as cutting oils, hydraulic fluids, etc.,against breakdown by bacteria which metabolize the hydrocarbons with theconcurrent formation of deleterious metabolites.

Many compounds have been used as stabilization agents in lubricants, butvery few have been found to be commercially successful due to the factthat the compounds are unstable, or are not active against a widevariety of microorganisms.

Among the nitroamines having the above structural formula are included2-nitro-2-methyl-l,3-bis(dibutylamino)propane,2-nitro-2-methyl-l,3-bis(Z-hydroxypropyl)aminopropane,2-nitro-2-methyl-1,3-dimorpholinopropane,2-nitro-2-methyl-l,3-dipiperidylpropane, and2-mitro-2-ethyl-1,3-bis(dimethylamino)propane. I have found that in someinstances I can obtain total inhibition of bacterial growth in petroleumlubricants at concentrations as low as 100 ppm. I prefer to include atleast 1,000 p.p.m. in most petroleum formulations. However, I can employamounts up to about 2% by weight of the active nitroamines when thelatter is soluble to this extent in the particular petroleum hydrocarboncomposition.

I have found that my active ingredients are effective bacteriostaticagents in petroleum containing lubricants such as cutting oils,penetrating oils, grinding lubricants, iron tinning lubricants, coreoils, hydraulic fluids, etc.

The following examples set out lubricating compositions :in which myactive ingredients act as effective bacteriostatic agents. It is notintended that my invention be limited to the compositions, portions, orlubricants set out below; but rather I intend for all equivalents andvariations obvious to those skilled in the art to be included within thescope of this specification and the attached claims.

Example I To test the use of my active ingredients in cutting oils, a25:1 water-cutting oil emulsion was prepared. The cutting oilconcentrate used was a proprietary cutting oil containing no bacterialinhibitors sold by Texaco Incorporated under the name of Soluble OilTexaco-C. To each of one-gallon containers was added '1 liter ofwatercutting oil emulsion. Desired amounts of my nitroamines were addedto the cutting-oil emulsion in the first container. No inhibitor wasadded to the other container which was used as a control. At thebeginning of the experiment, each unit was inoculated with 5 mls. of aheterogeneous bacterial culture which had grown for several years in awater-cutting oil emulsion. Aeration and mixing were obtained by usingan air lift to continually circulate the mixture. The test was continuedfor a period of six weeks and during the siX-week period, 5 mls. ofbacterial culture were added at periodic weekly intervals. I V

The following table sets out the results of the above tests and thenumber of days of bacterial inhibition when the described concentrationof the desired nitroamines were incorporated into the cutting-oilemulsion.

Table I Coucentra- Number Nitroamine tion in :1 of days water-cuttingeffective oil emulsion 42 2-nitro-2'ethyl-l,3-bis(dimethylamino)propane.250 1 -2 2-nitro-2-methyl-1,3-dirn0rph'ol1nopropane..2-nitro-2-methyl-1,3-dipiperidylpropane 1, 000 42 Control 0 Example IIExample 111 The following is a stabilized steam cylinder oil which isadequately protected by 1,000 ppm. of 2-nitro-2-methyl-1,3-bis(dibutylamino) propane.

Percent by weight S.A.E. lubricating oil Oleic acid 10 Example IV Thefollowing is a core oil which is adequately protected by 1,000 ppm. ofZ-nitro-Z-methyl-l,3-bis(2-hydroxypropyl) aminoprop ane.

Percent by weight Crude tall oil 25 Fuel oil 35 Tall oil ester (glycolor glycerol) 40 Example V The following is a cutting oil which isadequately protected by 1,000 ppm. of2-nitro-2-ethyl-1,3-bis(dimethylamino) propane.

Percent by weight Tallow 65 Paratfin wax 29 Beeswax 1.3 Oxalic acid 1.3Potassium citrate 1.3 Urea 0.4

Now having described my invention, what I claim is: 1. A liquidpetroleum lubricant composition consisting essentially of a liquidpetroleum lubricant and a sufiicient amount of a nitroamine to stabilizesaid lubricant against metabolizing bacteria, said nitroamine having thestructural formula:

R Ri-OHz( J-CHz-R1 wherein R is lower alkyl and hydrogen and wherein Ris selected from the group consisting of the radical N (R the morpholinoradical and the piperidyl radical and R is selected from the groupconsisting of lower alkyl, lower hydroxyl alkyl, and hydrogen.

2. A liquid'petroleum lubricant composition consisting essentially of aliquid petroleum lubricantand a sufficient amount of2-nitro-2-ethyl1,3-bis(dimethylaminohprop ane to stabilize saidlubricant against metabolizing bacteria.

3. A liquid petroleum lubricant composition consisting essentially of aliquid petroleum lubricant and a sufiicient amount Of 2-nitro-2-methyll,3-bis dibutylainino propane to stabilize said lubricant againstmetabolizing bacteria.

4. A liquid petroleum lubricant composition consisting essentially of aliquid petroleum lubricant and a suflicient amount 0f=2-nitro-2-methyl-1,3-dimorpholinopr0pane to stabilize said lubricantagainst metabolizing bacteria.

A liquid petroleum lubricant composition consisting essentially of aliquid petroleum lubricant and a suflicient amount of 2 nitro 2methyl-1,3-bis(2-hydroxypropyl) aminopropane to stabilize said lubricantagainst metabolizing bacteria.

6. A liquid petroleum lubricant composition consisting essentially of aliquid petroleum lubricant and a sufiicient amount ofZ-nitro-Z-methyl-1,3-dipiperidylpropane to stabilize said lubricantagainst metabolizing bacteria.

'7. An aqueous petroleum emulsion consisting essentially of an aqueouspetroleum lubricant emulsion and a sutficient amount of a nitroainine tostabilize said lubricant against metabolizing bacteria, said nitroaminehaving the structural formula:

wherein R is lower alkyl and hydrogen and wherein R is selected from thegroup consisting of the radial References Cited by the Examiner UNITEDSTATES PATENTS 2,381,408 8/45 Senkus 167-22 XR 2,474,791 6/ 49 Senkus260-247 2,913,414 11/59 Hodge 25251.5 2,976,244 1 3/61 Bennett 252-51.52,987,479 6/61 Bennett .252-5l.5 3,054,748 9/62 Hodge l67 22 DANIEL E.WY MAN, Primary Examiner; JULIUS GREENWALD, ALPHONSO D. SULLIVAN,

Examiners.

1. A LIQUID PETROLEUM LIBRICANT COMPOSITION CONSISTING ESSENTIALLY OF ALIQUID PETROLEUM LUBRICANT AND A SUFFICIENT AMOUNT OF A NITROAMINE TOSTABILIZE SAID LUBRICANT AGAINST METABOLIZING BACTERIA, SAID NITROAMINEHAVING THE STRUCTUREAL FORMULA: